import datetime

class State():
    def __init__(self, hit_id):
        self.time = datetime.datetime.now()
        self.hit_id = params['hit_id']

    def transition(self, transitionName, params = {}):
        raise Exception("Not implemented")

class StateMachine:
    def __init__(self, initalState):
        self.history = [('init',initialState)]

    def current(self):
        return self.history[-1][1]

    def transition(self, transitionName, params):
        # TODO: update Store & Interface
        if transitionName not in self.current().availableTransitions:
            raise Exception("Invalid transition")

        newState = self.current().transition(transitionName, params)
        if not newState:
            raise RuntimeException(f"Invalid transition {transitionName} for {self.current()}")

        self.history.append((transitionName, newState))

    def getStateForHit(self, hit_id, stateCls = None):
        states = [s for s in self.history if s[1].hit_id == hit_id and (stateCls is None or isinstance(s[1], stateCls))]
        if len(states < 1):
            return None
        return states[-1]

class HITCreated(State):
    availableTransitions = ['accept']

    self.state = None
    self.fee = None
    self.hit_created = None
    self.hit_opened = None
    self.hit_submitted = None
    def transition(self, transitionName, params = {}):
        if transitionName == 'accept':
            return HITAssigned(params['hit_id'], params['assignment_id'])

class HITAssigned(State):
    availableTransitions = ['reject', 'abandon', 'submit']

    def __init__(self, hit_id):
        self.assignment_id = None
        self.worker_id = None
        self.ip = None
        self.location = None
        self.browser = None
        self.os = None
        self.resolution = None

    def transition(self, transitionName, params = {}):
        if transitionName == 'reject' or transitionName == 'abandon':
            return HITAbandonedRejected(params['hit_id'])
        if transitionName == 'submit':
            return HITSubmitted(params['hit_id'])

class HITAbandonedRejected(State):
    availableTransitions = ['accept']
    def transition(self, transitionName, params = {}):
        if transitionName == 'accept':
            return HITAssigned(params['hit_id'])

class HITSubmitted(State):
    availableTransitions = ['scan']
    def transition(self, transitionName, params = {}):
        if transitionName == 'scan':
            return Scanning(params['hit_id'])

class Scanning(State):
    availableTransitions = ['scan_complete', 'scan_failed']
    def transition(self, transitionName, params = {}):
        if transitionName == 'scan_complete':
            return ImageAvailable(params['hit_id'])
        if transitionName == 'scan_failed':
            raise Exception("Scan failed, unknown state")

class ImageAvailable(State):
    availableTransitions = ['create_hit']
    def transition(self, transitionName, params = {}):
        if transitionName == 'create_hit':
            return HITCreated(params['hit_id'])